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Bmpcc6k pro Strong Banding issue

PostPosted: Sat May 15, 2021 8:57 pm
by tomlight
Hi,
in my BMPCC6k PRO sometimes I have a strong banding problems as you can see from attachments (line are Red because of the Focus Assist is turned on). Sometimes is strong, other times is subtle and I can barely see it. The problem is that I don't know how to recreate it, it happens suddlenly for a few seconds and then it stops.

It's not on the monitor but on the recorded files: both braw and prores.

Any advice?

[url]
https://drive.google.com/file/d/1SibHNb ... sp=sharing[/url]

https://drive.google.com/file/d/1SibHNb ... sp=sharing

thanks

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Sat May 15, 2021 9:27 pm
by Robert Niessner
I'd say contact Blackmagic support. Hard to say what's going on here.

BTW, that is NOT banding. Banding is when you can see steps in a color gradient

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Sat May 15, 2021 9:48 pm
by tomlight
Thanks Robert for your advice, I will contact BMD support.
How would you call this kind of problem? I know banding is a different thing but I wonder how it can be named.

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Sat May 15, 2021 10:34 pm
by Robert Niessner
Maybe it can be called lines of interferences. But I think we need some help here from English native speakers.

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Sat May 15, 2021 11:17 pm
by rick.lang
Are the lines stationary or moving down the screen?

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Sun May 16, 2021 8:44 am
by tomlight
Lines was moving with different amplitude.

[url]https://drive.google.com/file/d/1SibHNbQkuf7NxUV2aZpYA2uSJPAc_VTo/view?usp=sharing/url]

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Sun May 16, 2021 3:12 pm
by Johannes Jonsson
As Robert said, this looks like interference floating around the screen and the focus assist makes it look red colored.

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Mon May 17, 2021 7:34 am
by tomlight
I'm trying to replicate the problem and I noticed horizontal interference visible in particular at iso 800/1000 (far less visible at iso 5000 and beyond). The video below was shot with no lights and you can see the horizontal interference

https://streamable.com/xbgak7

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Mon May 17, 2021 12:00 pm
by Howard Roll
It looks a lot like EMI. You can see the interference tracks with the position of the camera at 7-9 seconds. Watch it in slow-mo, the camera pans into the interference and the band of noise propagates until the blacks are saturated, then as the camera is panned back across the same spot the interference unloads in reverse. This is about where it starts.

emi.jpg
emi.jpg (76.3 KiB) Viewed 418 times


These cameras seem a little sensitive to EMI, or RF, or something. The camera is powered internally, is it connected to anything else like a recorder or TX? Sometimes a simple ferrite choke will be sufficient for removing EMI on the wire. If the camera is picking up EMI/RF internally another solution may be in order.

signs.jpg
signs.jpg (153.92 KiB) Viewed 418 times


Good Luck

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Mon May 17, 2021 12:40 pm
by tomlight
Thank you very much Howard for your explanation.
Before the BMPCC6K PRO pro I had the regular 6k but I had never had this problem.
The test I did was shot in natural light and the camera was powered internally by the original battery.Nothing was connected to udbc or hdmi.
I have now tried to approach a small ferrite chokes as you suggested but I can't see any change. However I think a malfunction like this is not acceptable. I wrote to BLACKMAGIC and I'am waiting for a reply.

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Tue May 18, 2021 2:33 am
by Kristian Lam
Hi tomlight,

This is not acceptable. I would definitely RMA this camera. Please PM me your ticket number if you have already lodged a support ticket.

Re: Bmpcc6k pro Strong Banding issue

PostPosted: Tue May 18, 2021 8:03 am
by tomlight
Thank's Kristian for your help. The ticket number I received after the support ticket (found in the automated response email) is:

[Support #KOO-685-41528]: Strong Interference/Banding BMPCC6K PRO

I hope this help.

thanks